Keystone Sub Using 18, 15, & 12 Inch Speakers

I've been going through to topic to find speaker placement for more than two subs... maybe i have missed.. is it possible to couple the subs like the first picture or just leave them all side by side..

Thanks

D
 

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Tonefarm,

Either stack will work. Variations in the pattern in the upper response will occur, the "side by side" will have more narrow horizontal pattern than a single, the 2x2 will be slightly less narrow than the 4x1 horizontally, and more narrow vertically.

The image below would result in a more uniform pattern than either of the above, wider horizontally, and more narrow vertical. It would also be the easiest configuration to employ 4'x8' "Barn Doors" either side, increasing output by around 3 dB, like doubling amp power with no thermal compression or distortion.

Art
 

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Tonefarm,

Either stack will work. Variations in the pattern in the upper response will occur, the "side by side" will have more narrow horizontal pattern than a single, the 2x2 will be slightly less narrow than the 4x1 horizontally, and more narrow vertically.

The image below would result in a more uniform pattern than either of the above, wider horizontally, and more narrow vertical. It would also be the easiest configuration to employ 4'x8' "Barn Doors" either side, increasing output by around 3 dB, like doubling amp power with no thermal compression or distortion.

Art

Art, I've tried one on top of each other (2 x vertical) with large barn doors, when I find the photos I'll post them. Very impressive with the barn doors but quite directional, in fact too directional for a small near field event - at 50 -80 meters, well that was ideal.

I'll be experimenting soon with 2 x 2 horizontally on their sides. I'll report back.

cheers
Martin
 
18PW1400FE

Hey all.


First time post, but big fan of the site. Between here and (free)speakerplans I dread to think how many hours have been spent reading and thinking.


Anyway, to the point. I was hoping that Art might be able to answer this question personaly, being the designer and all. I live in Spain and therefore have access to Beyma drivers at a very good price. I plan on building a pair of keystones in the next 2 or 3 months (my first tapered horns), just as soon as I finnish off my new midtops; im going to have a crack at the old DIY folded horn from 100 to 270hz puzzle and build some 3 way FLH tops with some phase plugged 10 inch mids Ive had knocking about for ages (Martin Audio H3 style). It seems that the best driver for the keystone (bang for buck) in my situation is the Beyma 18PW1400FE.



ALTAVOZ 18"PW1400Fe 8 OH


They work out a good bit cheaper than even the 18TBW100 here in Madrid. To my eyes, they look like they should work well, seeming to sit somewhere between the BnC 150 and 100 in terms of TS parameters. However, I would like to take advantage of the luxuary of asking the designer directly before diving in.


So what do you think Art. Is there anything that sticks out there that makes you think these drivers would not be appropriate?


BTW, ive been following your design here for over a year now and itching to build some. Finally got an excuse to do it. Fantastic work, I have no doubt they will impress, mostly because of the evident atention to detail . Thanks for your work.


Cheers,
Dave.
 
It seems that the best driver for the keystone (bang for buck) in my situation is the Beyma 18PW1400FE.

So what do you think Art. Is there anything that sticks out there that makes you think these drivers would not be appropriate?
Dave,

I have no personal experience with Beyma drivers.
At 10mm excursion, and output will be less than the the B&C drivers suggested.

Hornresp inputs are available in post #96 and #130 so you might simulate the "bang for the buck" between them.

Cheers,
Art
 
Hey Art

Thanks so much for your swift reply.

Yea the Xmas point was clear, 2mm less than the TBW100 is no laughing matter, the same as the diference between the b&c 100 and 150. Ive not done any sims of the KS, been quite busy getting ready to prototype the folded bass horn im working on, not to mention the usual day job time constraints. Ill do a few sims before I make a final decision.

The diference in 'bang' is 2mm worth of displacement/distortion at peak levels (no danger of hurting the drivers displacement wise, they have an Xvar of like 48mm p to p, or something like that). Yet the difference in `buck' is 40% (compared to the TBW100) not to mention availability spares etc.

Beyma drivers are of very high quality, I would strongly recomend them and I think they are highily underrated.

I cant thank you enough for your input, I was worried there might have been something there which I had overlooked and I feel that I can now make a more informed decision.


Cheers

Dave
 
Wow. Looks really good. Im having trouble taking screenshots on my laptop atm and frankly its way too late for me to sort it out now, but ill try and get on it tomorrow so you guys can see for yourself.

Its a bit less peaky than the TBW100. Simmed a 1pi (which is how I plan to run them) it has its bottom peak at 44hz@107.4db, the bottom of the 'valley' in the middle is at 36hz@106.3db, and the upper peak is at 118hz@108.5db. It then has a sharp little spike at 128hz that goes up about another 1db or so, but thats well out of range for me, so not too relevant.

Fantastic!! im chuffed. When I ran the first sim I got this ugly curve with a big hump a 65ish hz rolling of by abour 3 db or so to wither end of the range and a terrible excursion curve, but checking over my inputs i realised id spaced out on one of the inputs. phew!!

This is great news for me, and frankly for anyone planing on building these in spain. these are super cheap here. Buying smart, you could build these for about 300 euros + wood/paint!! Ill be sure to post results when we get them going.

The only spanner in the works I can see (apart from less displacement) is the ever so slightly lower Mms 230g vs 245g on the TBW100. Not much, but with all the comments on how tough the KS is on cones......

Ill post the english spec sheet here, as I just noticed the link I posted before was in spanish. https://www.beyma.com/speakers/Fich...s-data-sheet-low-mid-frequency-18PW1400Fe.pdf

Thanks loads Art. Fantastic work.


Cheers,

Dave
 
Hi All,

I made a Keystone this weekend and want to say thanks to everyone on this forum who contributed. I did a lot of research on here before deciding to build one of these bad boys, and honestly was blown away by the performance! One KS run with 1000+w easily ran over two 1000w powered QSC KW181's unless I stacked them (then the QSCs could hang, barely - but only by adding in an extra 18 - there's simply no comparison between this and a QSC single ported 18).

For the comparison I put on Daft Punk's "Doing it Right" and the bass hits throughout are just incredible with the Keystone vs. the QSC. The QSC sound good just not the same output or gut feel. Unless you heard them A/B'd you'd never believe it was possible for 1x18 to sound more than subjectively better but it does - more output, more directional, and more "punch"! I followed up the Daft Punk with some Toto, and then some Bob Marley/Lauren Hill - the KS reinforced the musicality of the low end and added impact without sounding harsh.

The KS is an incredibly punchy sub! I'm running it with 1650w using an 8-ohm B&C 18SW100 and high passed at 30 (BW 48) its a really musical subwoofer even up higher than I need it to be, honestly. Right now I'm giving it a slight EQ bump around 35Hz, otherwise run flat. I plan to deploy these in two groups of two (8 ohms per KS, presenting a 4-ohm load to my Crown MA 2400's which are run bridged mono), so now have three more to build.

Here's some pics after routing the edges and applying bondo. Plan to sand and duratex next weekend, then get started on building 3 more in the upcoming weeks. Used 13-ply BB/BB, 1-1/4" cabinet grade plywood screws, and Gorilla Glue.

XRLmjYW.jpg
 
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One KS run with 1000+w easily ran over two 1000w powered QSC KW181's unless I stacked them (then the QSCs could hang, barely - but only by adding in an extra 18 - there's simply no comparison between this and a QSC single ported 18).
I plan to deploy these in two groups of two (8 ohms per KS, presenting a 4-ohm load to my Crown MA 2400's which are run bridged mono), so now have three more to build.
Tazunemono,

Thanks for sharing your comparison!

The Crown MA-2400 does 1585W bridge mono @ 8 Ohm, 2070w bridge mono @ 8 Ohm, you still have around another 3-6 dB more punch available from the B&C 18SW100 if you increase peak power.

Have fun!

Art